Maybe I am presuming...
But most coffee is roasted light to dark. People confuse strength of caffeine, and light acidic roast to a dark French roast.
Smokey and charred coffee isn't stronger. The 5 rating is more the burnt nature of the beans than the whack you get from it.
People assume a dark roast is stronger. Often it's just like comparing a cooking apple to a stewed apple. They are both the same but one tastes stronger.